1. Field of the Invention:
The present invention relates to an oil separator for a blowby gas ventilation system of an internal combustion engine and specifically relates to an oil separator for reducing the amount of oil ventilated to an intake path of the internal combustion engine.
2. Description of the Prior Art:
An oil separator is provided in the blowby gas ventilation system of an internal combustion engine for the purpose of separating oil from the blowby gas and reducing an amount of oil which is ventilated to the intake path of the internal combustion engine and burnt in the combustion chamber of the engine. The oil separator is provided above the camshaft in the cylinder head cover, in which oil drops splashed by the rotating camshaft and oil mist are filled, and separates oil from the blowby gas. The conventional oil separator is constructed of a baffle plate giving the blowby gas path a plurality of enlarged cross-sections and throttled cross-sections for the purpose of causing velocity differences between the oil and the blowby gas due to the inertia differences thereof, thereby increasing the degree of oil separation. However, such an oil separator is insufficient in separating oil from the blowby gas because fine oil drops and oil mist included in the blowby gas have nearly the same velocity as the blowby gas and can easily pass through the oil separator together with the blowby gas.
To increase the oil separating ability of the oil separator, it is presumed possible to install an oil filter in the blowby gas path and to let the blowby gas flowing to the intake path of the internal combustion engine flow through the filter. When the blowby gas path is formed between the top wall of the cylinder head cover and the baffle plate housed in the cylinder head cover, the oil filter should extend from the top wall of the cylinder head cover to the baffle plate in the vertical direction to let the entire amount of the blowby gas flowing to the intake path of the engine flow through the filter.
However, if the filter is provided in the above-mentioned manner, the oil which is separated from the blowby gas by the oil filter will flow downward in the oil filter and/or along the upstream side surface of the oil filter and will collect on the upper surface of the baffle plate in the vicinity of the oil filter. The collecting oil is blown due to the flow of the blowby gas and easily passes through the oil filter, resulting in decreasing the filtering ability of the oil filter and increasing oil consumption.